Borrowings - Schedule of Short-term Borrowings (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Short-term Debt [Line Items]
Amount	$ 2,772,998	$ 2,669,145
Weighted-average Rate	0.47%	1.75%
FHLB advances
Short-term Debt [Line Items]
Amount	$ 2,550,000	$ 2,450,000
Weighted-average Rate	0.49%	1.85%
Collateralized Deposits
Short-term Debt [Line Items]
Amount	$ 222,998	$ 219,145
Weighted-average Rate	0.25%	0.64%